The aviation security industry has a clear and pressing need for improvements in security effectiveness while reducing costs of operations. There has been a vastly increased emphasis on improving national security since the terrorist attacks of Sep. 11, 2001. Current bag/item screening methods at entry points to secure areas in airports and other security sensitive installations are essentially manual systems that take a little advantage of today's computerized technologies. Typically, situated at the entry to an airport concourse, for instance, is a security checkpoint station having x-ray scanners for inspection of carry-on bags/items. An inspector (screener) who examines the x-ray images of bags/items passing through a scanner is stationed at each scanner. If a screener sees a potential threat object in an x-ray image, he/she typically suspends image scanning and inspection and verbally alerts search personnel stationed in the vicinity of the x-ray machine conveyor to remove the bag/item in question to search for the object. Often the search person is called over to the x-ray image monitor to look at the object on the screen to help in the search of the bag/item. In the meantime, flow of traffic through the security checkpoint halts while this communication is going on. Lines at these x-ray machines are often long and can be quite slow, especially with today's increased threats of terrorism. Current processing rates through a typical security checkpoint are relatively slow and labor costs are high. The Transportation Security Administration's (TSA) FY2004 projected airport screener labor costs are $1.36 billion accounting for over 75% of the TSA budget for airport passenger screening. TSA has publicly expressed a desire to reduce the labor costs associated with passenger and baggage screening.
The rate of flow of people and their carried baggage/items through security checkpoints such as in airport concourses or other entrances to secure premises is limited in present day systems which have a single image screening inspection station associated with each x-ray scanner and which require that manual visual inspection by a screener (security person) at that inspection station of an x-ray image resulting from a scan be completed before the next image scan can be taken by the x-ray scanner. An x-ray image produced from the scanning may show an individual bag, an individual item, or a group of bags and/or items depending upon how they are presented to the scanner (ie. singly or in groups). In this document reference to a bag/item, bags/items, bags, baggage, items, articles, or similar reference is meant to include any of single articles as well as grouped articles presented to the scanner. The x-ray scanner generates an electronic image of a bag/item being scanned as the bag/item passes through the x-ray scanning region. The image is displayed on the scanner's screener inspection station monitor screen. Visual inspection of the image must be completed before another bag/item is scanned since a subsequent scan causes the displayed image to be replaced with a new x-ray image generated by the new scan. In today's scanners the scanning conveyor is controlled by the screener at the single screener inspection station and is stopped by the screener after each x-ray scan of a bag/item to allow the screener to visually inspect the image and decide whether to clear the bag/item or to call for a manual search of the bag/item. After completing visual inspection and, if needed, verbally notifying search personnel to search a scanned bag/item and assisting the search personnel in locating and removing the bag/item if it needs to be searched, the screener activates the scanner conveyor and scans the next bag/item. This sequence is repeated for each bag/item scanned for inspection. Consequently the flow of bags and items such as trays containing a collection of loose objects, packages, etc. and the advance of persons carrying these bags/items through the checkpoint can progress no faster through the system than the rate of conveyor manipulation and manual visual examination of each x-ray image by a single screener. Typically included in the time needed for the screener to complete the screening (inspection) of a bag/item are (1) the time required to start the conveyor and control the conveying of the bag/item through the scan zone to take a scan and then stop the conveyor, (2) the time needed to visually examine the resulting x-ray image, (3) the time required to make a decision to clear the bag/item or call for a manual search, (4) in the event of a decision to call for a manual search the time required to verbally notify search personnel of what to search for, and (5) manipulation of conveyor position so that the searcher can locate and retrieve the bag/item to be searched.
As a result of the limitations discussed above the x-ray scanning equipment, associated conveying systems, peripheral equipment such as metal detectors and explosives detection systems, and a team of trained security personnel to man and operate the security checkpoint are limited to processing bags/items and their associated persons at a rate limited by time requirements for one screener to perform scanner start and stop operations for every bag/item scanned, time required for that same screener to visually examine every x-ray image produced, time required for that same screener to verbally alert search personnel to any bags/items that need manual search, time required for that same screener to verbally convey to the search personnel what they should be looking for within the suspect bag/item, and time required for that same screener to assist the search personnel in locating and securing the suspect bag/item. According to TSA personnel at the Nashville International Airport, present day average throughput rate of bags/items through an x-ray scanner is approximately 150 bags/items per hour. They have said that 200 bags/items per hour is top rate during rush periods.
As discussed in the following, and as provided by the present invention, many more bags/items can be scanned through the system in a given period, and thus pass through the checkpoint, allowing a greater flow of people and their carried items to be cleared through the checkpoint if requirements for a screener to stop/start the scanning operation during each x-ray image inspection is reduced or eliminated. In the present invention, multiple screener image inspection stations can be utilized to simultaneously inspect multiple different x-ray images if needed such that bags/items continue to be scanned during the times that x-ray images are being visually inspected, and screeners are relieved of the need to verbally communicate to search personnel information concerning bags/items to be searched.